builtins.fetchTarball {url="https://github.com/NixOS/nixpkgs-channels/archive/d1265562b4c3cca8922f680ee504fa6bd875cae6.tar.gz"; sha256="0qdyiasjdzamlr7jf311wslsvz2cy15cnn8gjj4dr7pwb0wdysp2";}